Yes, hometree is an ejabberd specific implementation of a simple tree,
to make node ordering simple and clean
Default plugin is now flat, what allow flat nodenames as described in
XEP-60 (i.e. xep examples will work)
dag indeed implement the dag spec of xep-248
mb is for microblogging, based on pep
private public dispatch club buddy, are simple plugins, all based on
hometree, but with different default node configuration, giving them the
desired behavior.
example, private have whitelist as default access_model
all should be ready for production, as they are using base plugins.
anyway, flat hometree and pep are the default standard and tested
plugins.